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Update 0404.左叶子之和.md

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勘误python注释
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2021-10-08 13:12:08 +08:00
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problems/0404.左叶子之和.md
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@ -171,10 +171,10 @@ class Solution {
int rightValue = sumOfLeftLeaves(root.right); // 右 int rightValue = sumOfLeftLeaves(root.right); // 右
int midValue = 0; int midValue = 0;
if (root.left != null && root.left.left == null && root.left.right == null) { // 中 if (root.left != null && root.left.left == null && root.left.right == null) {
midValue = root.left.val; midValue = root.left.val;
} }
int sum = midValue + leftValue + rightValue; int sum = midValue + leftValue + rightValue; // 中
return sum; return sum;
} }
} }
@ -242,37 +242,10 @@ class Solution:
cur_left_leaf_val = 0 cur_left_leaf_val = 0
if root.left and not root.left.left and not root.left.right: if root.left and not root.left.left and not root.left.right:
cur_left_leaf_val = root.left.val # 中 cur_left_leaf_val = root.left.val
return cur_left_leaf_val + left_left_leaves_sum + right_left_leaves_sum return cur_left_leaf_val + left_left_leaves_sum + right_left_leaves_sum # 中
``` ```
> 递归前序遍历
```python3
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def sumOfLeftLeaves(self, root: TreeNode) -> int:
# 需要通过中节点来判断其的左节点是否存在；左节点自己的左右节点也是否存在
if not root: return 0
# 初始化left_leaf备用
left_leaf = 0
# 若当前节点的左孩子就是左叶子
if root.left and not root.left.left and not root.left.right:
left_leaf = root.left.val
left_left_leaves_sum = self.sumOfLeftLeaves(root.left)
right_left_leaves_sum = self.sumOfLeftLeaves(root.right)
return left_leaf + left_left_leaves_sum + right_left_leaves_sum
```
> 迭代 > 迭代
```python3 ```python3